No Boundaries
by WrongLady
Summary: Nana is a single mother who raised his son alone. Her son, Sawada Tsunayoshi, is now 16 years old as his mother meets her new love Iemitsu. But he doesn't only bring himself in the house but also his two uneven "twins" Hibari Kyouya and Rokudo Mukuro. / 1827 / 6927 / 182769 / Rated M for a reason ( sex? )


**Title:** (No) Boundaries

 **Warning:** Grammar and spelling mistakes.

A lot of smut and sex and senseless actions in later chapters? And Yaoi, boy x boy. Don't like, don't read.

 **Pairings:** 1827 / 6927 / 182769 / others

 **Summary:** Nana is a single mother who raised his son alone. Her son, Sawada Tsunayoshi, is now 16 years old as his mother meets her new love Iemitsu. But he doesn't only bring himself in the house but also his two uneven "twins" Hibari Kyouya and Rokudo Mukuro.

 **A/N:** I can't imagine Nana with someone else than Iemitsu so I made him her new husband, etc. Ya know? To explain beforehand I read about a phenomenon with a woman having two uteri so I thought I made Hibari and Mukuro "twins". So… to explain their different names xD In the story I will explain it further! Also can you find the house there they will be linked in my profile ( password: yaoi182769 ). I like doing such house making stuff so I just made some – for fun –lol- The furniture are just for show ^-^ And maybe you would understand more about the room constellations!

Hope you enjoy!

* * *

It started one and a half month ago with Sawada Tsunayoshi's noticing his mother's summing in the kitchen. She always sums in the kitchen then she cooks but he noticed on the song his mother chose to sum. It was definitely a love song.

The second time Tsunayoshi got suspicious as he came home from school and before he could say 'hi' to Nana he accidently eavesdropped a conversation of his mother talking to someone over the phone. She was all smiley and shiny and giggled like a high school girl. Tsuna found this a bit disturbing.

One time Nana accidently mentioned a 'he' as she was scolding him because of his bad notes from school. She could barely hide the fact she was seeing someone new.

The other time his mother told him she was meeting an old friend and left for the evening and as she came back Tsuna could hear from the house door a male friend and his mother's happy giggle.

It wasn't in such a way if he did not grant it to her but it was nevertheless an odd feeling to have his mother in that way. She was a bundle of happiness – more than she already was and it was quite annoying how happy she was. But he was pleased that she could be happy again. After his father left them Nana raised him alone and it was really hard. For a few years they lived in Nana's parent's house and Nana worked hard to effort an apartment for her and her son. Tsuna helped his mother as much as he could as he was a kid. Still today he tried to help her but he was rather clumsy that he made things worse than better. But Nana appreciated his help and didn't complain much.

So Tsuna decided to talk to her about _that_ matter. It was a Friday evening. Even though most of the teenagers in Tsuna's age spend the day with his friends and other teenage things Tsuna wasn't like other teenagers. He didn't have any friends. He spent the day at home, mostly playing video games. But now he sat on the table and watched his mother cooking.

He stared at her back and waited that Nana would notice something but she just ignored her son's stares. Tsuna sighed. "So, oka-san. Who is it?" Tsuna finally asked and he watched his mother shrugged.

"W-who is who?" Nana asked innocently and acted if she didn't understand. Tsuna thought about it. Did he really want to know? Not really… but now he already asked. "Your… new…eh… boyfriend?" It sounded so wrong.

Nana turned around to Tsuna, looking at him a bit shocked. "You…. How… oh my god, Tsu-kun!" Her cheeks turned red and a shy smile appeared on her face. "You noticed?" Tsuna frowned and smiled a bit. "Uh, yeah… obviously."

He tensed as Nana sat down next to him and grabbed his hands. Oh-oh. Tsuna looked at his mum's eyes. They were all shiny and excited but also quite serious. What a mix. "You see… Mama was really busy with raising you, right?" she began. Tsuna nodded. "And you know… how your father left you-" "He also left you," he murmured. Nana just smiled and patted his hand. "All I was thinking was raising you and so I… didn't really care for … other men."

Tsuna licked his lips. He didn't to hear this… he really didn't. Why did he bring this up?

"You were my world. You know that, do you?" Tsuna smiled a bit and nodded. "But…" Nana blushed and tried to hide a giggle. "You see… two month ago I met a … really great man. He was funny and he made me laugh again," she smiled lovingly, a smile Tsuna never saw on his mother's face. It was a bit shocking for Tsuna.

"He's great! He's really romantic and nice! He would love to meet you, Tsu-kun." Nana smiled brightly at him. Tsuna forced a smile on his lips which looked more like a forced grin. "W-well… would he?" he murmured. "And he has always two sons! They're twins! But they don't really look alike!"

Tsuna frowned. "You already meet them?" Nana nodded enthusiastically. "Yes! They are nice! They are just two years older! And… I want our two families… to be in one house." Nana radiated and Tsuna dropped his mouth. "You what?" "I want to be with him," Nana explained. "Give me his name first!" "Oh, his name's Iemitsu. You will like him!"

The brunet frowned. "But isn't it too soon?!"

* * *

"Sons, I need to talk to you." Iemitsu put the can of beer on the table and sat down to the dining table. In front of him sat his two sons Hibari Kyouya and Rokudo Mukuro. Two unequal twins. Well, you rather can call them brothers than twins… but later on this one.

Hibari sat unwillingly on that table with his father and his brother. He hated crowding and couldn't stand it if too many people are in the room. Most of the time he didn't care what his father had to tell but sometimes his father emitted an aura one couldn't just ignore…

Mukuro, on the other hand… well, you couldn't say that he liked being with them in one room but he coped with it. No matter how much he sometimes despise his 'loving' brother he can't ignore his father request because of a few reason he never talked about.

"So, you got to know Nana, right?" Iemitsu said and looked at his sons who didn't resemble him at all. His gens didn't fight hard enough… "Nana and I talked about this and came to the conclusion… That we will buy a house and move in together!" The blonde grinned widely and emitted happiness. Hibari's eyes narrowed. "What?" Before the raven haired boy could say something Mukuro interrupted him with his significant laugh. "Kufufufu, aren't we moving soon?" he chuckled but as displeased as Hibari.

"Well, you see, I'm not that young anymore and I want to spend my time with Nana! And she got an adorable son. I saw pictures of him!" Iemitsu stood up. "We already have good prospects of a house so… you should pack your things, boys." He knocked on the table and walked out of the room, leaving them before they can complain.

* * *

Two months later the house was bought and Nana and Tsuna were the first to arrive at the house at the official moving day. He was totally okay with changing schools… Tsuna sighed as he saw the big house in front of him. He was used to a smaller apartment and now he was moving into a big house with three people more he was used to.

"You liked the house! I showed you pictures!" Nana said and dragged him into the house. The house was really big. Too big for his liking. Tsuna sighed and scratched his head. "Don't drag me," he murmured and walked into the house. They had much to do in this house. A few boxes were already there, showing that the other family was here at some time. Tsuna didn't know _who_ exactly those sons were because Nana refused to tell him.

"Okay, let's bring some boxes into the house!" Nana walked out, leaving Tsuna in the house. He stood alone in the entrance hall and looked around. He walked to the door frame without a door itself, assuming this would be the living room and the kitchen. Leaving the living room he walked to the door on the opposite side. There a note stuck on the door. "Iemitsu's and Nana's room " was written on the note. Tsuna made a grimace.

He was quite glad that his mother found her new love but that they had to be all lovey-dovey… It was a disaster as he first met Iemitsu four weeks ago. He didn't dislike him but he also didn't like him. He wasn't that great as Nana had told him. Well, maybe Tsuna came to accept him fully. Nana was a grown-up, she could decide on her own. Tsuna never wanted to be the son who would persuade his mother because of his egoism. He saw that Nana was happy and really in love and so was Iemitsu. Tsuna could sense that, he had an eye for people who are truly in love. A really weird 'ability' he might have but it was an ability, so he didn't feel that bad. That it was his hyper intuition he couldn't have known that.

Ignoring the note he walked to the stairs, going upstairs. He looked around and opened the room which will be in future the guest room which wouldn't be in use for the current. He explored the next door to find a note on the door. "Your room, herbivore," stood on the note. Tsuna sweatdropped. "What?" he murmured and wondered who the 'herbivore' was. He opened the door and looked around. It looked usual, quite spacious but this house was very big. He turned around and wanted to explore the next floor level as he heard voices downstairs.

"Nanaaaa, I missed you so muuuch!" followed with a girly giggle was heard and Tsuna rolled his eyes. Oh gosh.

Tsuna decided to greet him instead of ignoring him. He walked the stairs downstairs.

And he wouldn't be Dame-Tsuna if he wouldn't trip on his own feet. He tried to hold himself on the banisters but it slipped out off his hands.

"Hiiieeee!"

Tsuna closed his eyes shut, made himself small do minimize the pain. He waited for a few minutes but still no pain. Instead of the hard floor Tsuna felt something more soft but also a bit… hard. Kinda boney. He also felt an arm around his waist…

Carefully he opened an eye, looked up. He looked in a handsome face, the eyes of the person were heterochromatic, he had blue hair and his hairstyle resembled … a pineapple. Well, the different colored eyes scared him somehow.

"Oya?" the male said with a mischievous grin. "I think an angel falls into my arms." He chuckled amused and Tsuna widened his eyes.

"Hiiieee?! I'm sorry!" Tsuna screamed and jumped back to trip over his feet again and landed on his backside. "Ow…" The brunet narrowed his eyes and after the slight pain vanished he looked up again. The other male still looked at him, chuckled amused. _Wait, did he just throw a pick up line on me?!_

"Oi, Mukuro."

Iemitsu appeared right next to the boy and looked at Tsuna. "Hi, Tsuna!" he said with a wide grin on his face. Tsuna forced a smile and got up. "Hello, eh, Iemitsu-san," he murmured. "Well, seems like you met one of my sons! Introduce yourself," the blonde commanded and Mukuro snorted and looked at Iemitsu.

Tsuna frowned. What was that look? Somehow his eyes were mixed with disgust and respect at the same time. Tsuna gulped. Oh well…

"I'm Rokudo Mukuro," the male finally explained and gave the brunet a grin. Tsuna smiled sheepishly. "N-nice to meet you, eh, Rokudo-kun," he said. "I'm Sawada Tsunayoshi." He bowed as he introduced himself. "Nice to m-meet you!"

"Kufufufu, you can call me Mukuro," Mukuro said, chuckling. Tsuna raised his head. "Oh, okay… then… you can call me Tsuna if you like." "It would be a pleasure," Mukuro grinned in a way Tsuna didn't understand the meaning of. He frowned and just smiled shyly.

"Oh, Tsu-kun!" Nana came running towards them. "Seems like you two already met! Did you introduce yourself probably?" Tsuna grumbled. "Of course," he murmured. Nana smiled brightly. "Didn't I tell you! My Tsu-kun is so cute!" Tsuna widened his eyes. "Ka-san! Stop!" he protested and couldn't hinder the slight blush on his cheeks. Mukuro grinned. "Yeah, sure he is," he said. Tsuna bit his tongue to not say something. He looked away and cleared his throat.

"So… aren't there two sons?" Tsuna quickly changed the subject. Iemitsu caught the question and sighed. "This idiot is patrolling again," he said and shrugged his head. "But… his love for Namimori is really… something." "Something stupid," Mukuro said quite coldly. "Who would love a small town like this so much?" He rolled his eyes.

Tsuna frowned and looked to Nana, who just smiled. "Okay, we have so many things. Boys, come and help us bring the boxes into the house!" Nana walked with Iemitsu out of the door and left Tsuna and Mukuro alone.

The brunet smiled a bit. "Eh… yeah… we should help," he murmured and passed Mukuro to help the adults with the transporting.

* * *

After Tsuna got to know that he was meant on the note as 'herbivore' he wasn't angry because they just decided over his head about the room. He was quite okay. He had the store level for himself…

So after Iemitsu and Mukuro helped him to put up his bed and desk he himself tried to put up his closet and he managed to fill his shelves and put away his things. He was almost done! He didn't have much. Not much clothing, not many books, not many things to store, so he was quite happy that he was so soon ready. It was almost 8pm. Tsuna looked out of the door. Out of his room window he could see the courtyard to the house entrance.

He saw something moving and narrowed his eyes. Was there someone?

"Tsu-kun! Dinner is ready!" Nana called for his son. Tsuna shrugged the movement outside off and walked to the stairs. "Call Muk-kun!" his mother added. Muk-kun? Tsuna sweatdropped. So he already got a nickname?

Tsuna sighed and walked to the third floor. He saw three doors. One of the doors was a little bathroom so … which one was Mukuro's room? He tried the door right in front of him. But millimeters away from the door knob he felt something hard and cold, like metal, on his nape. Tsuna widened his eyes.

"Herbivore, what do you think you are doing?" a deep voice asked which sounded _really_ pissed. A cold shiver ran down Tsuna's spine. "For intruding my room I will bite you to death." Tsuna shrugged and turned around. He didn't see much because the light was off and it was almost dark outside. He saw metal reflecting in the dim light of outside. He shut his eyes, covering his face with his arms and screamed his significant scream.

 _CLANG!_

The sound of metal crashing together ringed in his ears and he waited for a second, before sinking his arms and opened his eyes. He saw someone else in front of him, his back to him. He blinked. That hairdo… Mukuro?

"Kufufufu, what are you doing, Kyouya?" Mukuro said… Tsuna blinked. Mukuro…. Hold something in his hands. A trident? What? Tsuna widened his eyes as the light went on. He blinked because of the sudden light.

In front of him was Mukuro, really holding a trident, repelling an attack from tonfas. The owner of these tonfas was a raven black haired male, his skin was really pale in contrast to his hair. His eyes were cold and sharp. Tsuna shivered a bit.

"What are you guys doing?" The deep, kind of rough voice of Iemitsu made his way into Tsuna's ears and he looked to the stairs. He looked really serious… not something Tsuna would've expected from the man. Mukuro grinned. "I was just protecting your lover's son," he said and looked over his shoulder to Tsuna. Tsuna noticed and forced a polite smile. "… I'm sorry, Tsuna-kun," Iemitsu said and walked towards them. He stopped next to the stranger and looked down at him. "This is my other son. Hibari Kyouya. Hope he didn't do anything rude to you." Iemitsu grinned and put his fist on his hips.

Said male snorted displeased and glared at the blonde who would be supposed to be his father. Tsuna's hyper intuition rang but he couldn't lay a finger on it. Anyway he kind of knew that something was off in the relationship of these three people…

"Eh… I'm Sawada Tsunayoshi, n-nice to meet you, Hibari-san!" Tsuna bowed and bumped into Mukuro's back who was still half in front of him. Mukuro chuckled and Tsuna flinched. "S-sorry…" He rubbed his forehead and looked up.

"You are crowding," Hibari said and glared at Tsuna. Said boy flinched. _He's scary!_

Tsuna looked to Iemitsu who sighed. "Dinner's ready. Come eating, boys. Especially you two" Iemitsu turned around and walked down.

An awkward silence fell over the three boys and an amused chuckled was heard. "Kufufufu, we shouldn't let them wait, should we, Tsunayoshi?" Mukuro turned to him and put his hand on his back. "We should hurry." He gently pushed Tsuna to the stairs and exchanged with Hibari a cold glare. "Don't provoke things unnecessary," he whispered to the raven haired male. Hibari narrowed his eyes. He gripped his tonfas tighter, slightly shivering because of anger.

Tsuna looked over his shoulder to Hibari, while he was lead downstairs by Mukuro. "W-will he be okay?" he asked the bluenet and looked up to him. Mukuro shrugged his shoulders. "Who knows," he merely answered which displeased Tsuna but he didn't ask further. It wasn't his matter….

* * *

Tsuna learned over the time ( three weeks ) he lived with Mukuro and Hibari together that a) Mukuro was a damn pervert making always ambiguous sayings, b) Mukuro and Hibari seemed to hate each other and would fight against each other each time they cross path, c) Hibari hated more than three or four people in a room and would bite them to death, but d) Hibari had kind of a soft spot for Nana, because he couldn't escape her mama's force and e) Hibari and Mukuro have something against their own father but feeling forced to do things for him they didn't like.

Even though Tsuna was clumsy and a no-good his observation ability was superb. He noticed small things and sometimes he could analyze them right. But most of the time he didn't have the ability to analyze them.

He couldn't tell why those brothers would hate each other so much. Weren't they twins? But he could remember one time as Mukuro told him something. "We aren't exactly twins. We are just brothers getting to be born one after another." Tsuna didn't understand. That explained exactly that they were twins…

It was really complex and Tsuna didn't want to be drag into their weird mess what they call family. They weren't acting like a family at all; they were not even trying!

Tsuna sat on his desk and flicked through a game magazine as he saw a yellow fluffy-something on his window-sill. He opened the window and recognized Hibird, Hibari's little singing bird who could also talk. Well, at least it can say some words.

"Hello, Hibird," he said and smiled. Hibird was so cute and fluffy! "Herbivore, herbivore," Hibird chirped and hopped on Tsuna's hand who did offered it. Tsuna stroke over the fluffy fur of Hibird and giggled a bit. "Yes, yes, I'm a herbivore, I know," he said and stood up. "I bet, Hibari is missing you. I think he's upstairs." Tsuna walked out of the room and crossed the corridor to go upstairs.

With quiet steps he walked the steps up and soon arrived Hibari's room… as he heard something…

"You bastard, stop touching me," a husky voice said. "I'll… bite you to dempf-"

Tsuna frowned. They were at it again? But… that's not the way they were usually fighting. The door was leaned on so he dared a view inside…

… to see something really shocking for him. It took a while before he could turn around and ran downstairs, running into his room and locked the door.

"What the-"

* * *

 _I hope you liked it so far :x I really want to know what you do think about it!_

 ** _R &R?_**


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